Mechanical Performance Of Drillstring In6" Horizontal Well In Jidong Oilifeld

Slim-hole horizontal well contains the advantages of slim-hole Wells and horizontalWells, has a high rate of penetration, low drilling cost, cuttings and wastewater emissions, lesseasy to move, high capacity, etc. But, slim-hole horizontal well drilling has a big difficulty ofthe construction, not only the casing annulus gap is small but consumption and high pumppressure Drilling capacity is limited，the drill bit and screw size are small, the fiction of downhole and the torque is high, and horizontal section is complex loading, sticking, tool wear isserious and other technical problems, that brings very great difficulty of construction qualityand drilling speed.So this paper uses the nonlinear static analysis method, establish the model of down holedrilling tools non linear static, to analysis of the geometrical nonlinear equation of the drillstring’s beam element, the physical equation, the balance equation and stiffness matrix.Considering the contact problem of drill string and borehole wall, According to gap elementdiscriminated conditions and definite state of gap and gap elements balance equations draw aconclusion of the lower drilling tools of the finite element equations of the vertical andhorizontal bending. On the basis of above using three focal point circle, balance the curvaturemethod, bit/formation interaction model, resultant force method and the force anddeformation method to analysis. Concluded that compound drive drilling bending Angle’sinfluence on the rate of hole enlargement. At the same time considering the changes of thescrew bending angle, changes in the rate of borehole expansion, stabilizer to the bit length andstabilizer diameter changes, Borehole curvature changes and angle change to analysis theeffect of slim-hole horizontal well of the bottom hole At the scene application of the slim-holehorizontal well in jidong oilfield, and comparing the predicted results and actual results To beable to meet the requirements of drilling operation is in conformity with the tool designperformance. To analysis of the slim-hole horizontal well drill string mechanics performanceand through capacity, set up the taper thread connection strength mechanics model,considering the assembly, borehole configuration, process parameters and combining with theworking condition of the drill string with different Wells in the depth of the drill stringontology, threaded parts for strength calculation, final assembly are given by ability. Usecurved screw drilling tools, on the premise of meet the borehole trajectory control, in order toovercome the difficulty big directional drilling friction, pressure, has the disadvantages suchas proppant carrying capacity, usually adopt wheel rotation at low speed and common drillingscrew driver. In curved screw rotary drilling, rotary speed depends on the size of the drillstring can work safety, the drill string strength assessment. Draw a cone screw on therelationship between the torque and preload force.